1. Field of the Invention
The present invention relates to a vehicle seat with a back rest, a head restraint, which is adjustable in the height and which has a head cushion, and a ventilation device, whose exhaust vent for blowing out a warm airflow is arranged on the upper side of the back rest.
2. Description of the Related Art
Such a generic vehicle seat serves, particularly in the case of a convertible, the circulation in the neck area of a vehicle passenger, especially when the roof is open, in order to compensate for the draught. A generic vehicle seat is known, for example, from DE 10 2004 002 074 83. In this state of the art, a textile membrane extends between the upper side of the back rest and the head cushion, whereby this textile membrane covers the interspace provided in between and works as a diffuser, so that the warm airflow that issues from the back rest at the upper side of the back rest between the textile covering and the vehicle passenger is diverted in the direction of the vehicle passenger. On the side of the back rest, the textile covering is wound around via a winding mechanism, so that an adjustment of the textile covering to various positions of the head restraint relative to the back rest is possible. As is generally known, the position of the head restraint must be individually adjusted to the size of the vehicle passenger in order to protect the vehicle passenger in the event of an accident.
The aforementioned solution is relatively complex and furthermore unsightly, because it is not always possible to stretch the textile covering in such a way that there are no wrinkles. In addition, the dimensions of the covering must be adjusted to the position of supporting bars that support the head restraint and that are held in the back rest in such a way as to be displaceable.
In an alternative development known from DE 10047754, a multitude of air outlet openings are provided in the upper area of the back rest which surrounds the shoulder area, whereby these air outlet openings are intended to bring about a uniform air cushion in the shoulder and neck area of a passenger, namely on the basis of an airflow that is drawn in from the back side of the vehicle seat and pressed out forward through the cushion and covering of the back rest. This development requires uniform perforation of the upper area of the back rest, which leads to limitations with regard to the eligibility of suitable covers for the cushion of the back rest. In an alternative development, an air distribution device is integrated into the back rest, whereby this air distribution device is intended to deliver air to the shoulder, neck and head area of the passenger via various exhaust openings. This development is also relatively complex. In addition, the various exhaust openings should be avoided in the vehicle seat for aesthetic reasons. Furthermore, the known solution does not allow for a neck flow that is adapted to the individual size of the vehicle passenger. The neck is, however, the most sensitive part of humans, particularly as regards unpleasant draught currents.
In a further development known from DE 100 54 010, an exhaust pipe, the height of which can be adjusted, is attached to the back rest, whereby the exhaust vent of this exhaust pipe is integrated into the head restraint and this exhaust vent can be adjusted in the height along with the head restraint. In conventional vehicle seats, in which the head restraint is arranged so as to be elevated above the back rest, such a development leads to an unsightly development with a pipe piece between the upper side of the back rest and the head restraint. Furthermore, special measures, which make the design complex and expensive, must be taken in order to use pipes to form an airway that is airtight and that can be adjusted in the height.